Progress onNb3Sn and V3Si

Progress onNb3Sn and V3Si

Beijing, SRF2007 Padova University, Material Science Dept

S.M. Deambrosis*^, G. Keppel*, N. Patron*, N. Pretto,V. Rampazzo*, A. Rossi*^, R.G. Sharma°, S.Stark*, F. Stivanello* and V. Palmieri*^

* INFN - Legnaro National Labs^ Padua University, Science faculty, Material Science Dept

° Nuclear Science Centre, New Delhi

Liquid Sndiffusion

Hybrid Process

Double Furnace System

Samples

Samples

6 GHz

Mechanical Plating

6 GHz

Double Magnetron

Post Magnetron

Samples

6 GHz

NbNb33SnSn

Tin Diffusion Multilayer

Thermaldiffusion

Thermal Diffusion +

Plasma

SamplesSamples

6 GHz cavities

VV33SiSi

Nb3Sn can be obtained using different techniques:

Bronze Process,

Vapor Sn diffusion (Wuppertal),

Liquid Phase DiffusionLiquid Phase Diffusion Annealing

Beijing, SRF2007

Liquid Liquid SnSn DiffusionDiffusion

• No nucleation sites on Nb are required

• Fast growth of Nb3Sn layer

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Linearfeedtrough

Cooling water jacket

Furnace

Liquid Sn

Furnace

Liquid Liquid SnSn DiffusionDiffusion

Beijing, SRF2007

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

HybridHybrid1 step1 step 2 steps2 steps Now:

Cornell Workshop Peking Workshop Peking Workshop

Sn vaporAnnealing

VacuumAnnealing

Sn vapor Annealing+

Vacuum Annealing

Good Tcs, No residual Sn,

No spurious phases

Hybrid ProcessHybrid ProcessNbNb33SnSn NbNb33Sn at LNLSn at LNL--

Beijing, SRF2007

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

• residual Sn• spurious phases

• low Tcs• spurious phases

Hybrid Process: SamplesHybrid Process: Samples

Beijing, SRF2007

Proc T = 975°C, Dipp t = 30’, Ann (Sn) t = 2h, Ann t = 5h

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Angle 2θ (degrees)

Rela

tive

Int

ensi

ty

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Hybrid Process: SamplesHybrid Process: SamplesNbNb33SnSn NbNb33Sn at LNLSn at LNL--

Beijing, SRF2007

T = 975°C, tDipp = 30’, AnnSn t = 2h, AnnV t = 2h

Tc = 16,8 K

ΔTc = 0,16 K

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

“Hybrid” Method for Nb3Sn 6 GHz Cavities

Beijing, SRF2007

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Hybrid Process: 6 GHz cavitiesHybrid Process: 6 GHz cavitiesNbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

DoubleDouble FurnaceFurnace SystemSystem

Beijing, SRF2007

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Annealing Furnace

Dipping Furnace

Built to avoid air contamination of the superconducting thin film while opening the vacuum system

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Mechanical PlatingMechanical Plating

Beijing, SRF2007

Cavity- Mechanical etching- Chemical etching (1:1:1)

Sn pieces- Ultra sonic cleaning

Sn pieces after the treatment

A 6 GHz cavity in the working tumbler

Preliminary preparation:

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Experimentaldesign

Section view of experimental

devicesputtering

system

Balanced Magnetron sources

Target-Substrate

distance = 60 mm

2 inches target diameter

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Beijing, SRF2007

Multilayer: Double MagnetronMultilayer: Double MagnetronNbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Double Magnetron: SamplesDouble Magnetron: Samples

Beijing, SRF2007

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Tann= 600 °CTann= 700 °CTann= 800 °CTann= 930 °C

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Beijing, SRF2007

Double Magnetron: SamplesDouble Magnetron: SamplesNbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

16 17 180,0

0,4

0,8

R (O

hm)

2 A

T (K)

2A R600癈 2A R700癈 2A R800癈 2A R930癈

Tc max = 17.9 K

ΔTc = 0.02 K

RRR = 3.6

Tann= 600 °CTann= 700 °CTann= 800 °CTann= 930 °C

Beijing, SRF2007

NbNb33SnSn NbNb33Sn at LNLSn at LNL--

Double Magnetron: SamplesDouble Magnetron: Samples

Annealing T = 930°C

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Beijing, SRF2007

NbNb33Sn at LNLSn at LNL--NbNb33SnSn

Post Magnetron: 6 GHz CavitiesPost Magnetron: 6 GHz Cavities

Linear Feedthrough

Coil

Window

Water Cooling

Cavity

Cathode Nb(Yellow)/Sn(Green)

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Post Magnetron: 6 Post Magnetron: 6 GHzGHz CavitiesCavities

Beijing, SRF2007

NbNb33Sn at LNLSn at LNL--NbNb33SnSnNbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

NbNb33Sn at LNLSn at LNL--NbNb33SnSn

Beijing, SRF2007

Time of sputtering: 70 minAnnealing Time: 1 h at 850°C

Post Magnetron: 6 Post Magnetron: 6 GHzGHz CavitiesCavities

Nb3Sn multilayer 1: Q-value still lower than for bulk Nb 6 GHz

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Four hypotheses:

1) Sn evaporation due to plasma interaction with the growing film

2) Too thin Film

3) Spurious phases presence (slow annealing ramp time)

4) We suspect the substrate treatment requires even more

attention

Research for the best Chemical Treatment of V

Variables: T, t, p(SiH4)

Beijing, SRF2007

Thermal DiffusionThermal DiffusionVV33SiSi VV33Si at LNLSi at LNL--

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

• SiH4 Decomposition • Si Diffusion• V3Si Nucleation

• Film Growing• Recrystallization• H2 Removal

Beijing, SRF2007

VV33SiSi VV33Si at LNLSi at LNL--

Thermal Diffusion: Experimental Thermal Diffusion: Experimental SetUpSetUp

Nb

V substrates

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Beijing, SRF2007

VV33SiSi VV33Si at LNLSi at LNL--

Thermal Diffusion + Plasma: Experimental Thermal Diffusion + Plasma: Experimental SetUpSetUp

V substrates

Electrode

Lamps on

Plasma on

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Angle (2θ)

Rela

tive

Int

ensi

ty

Process T = 825°C, p (SiH4) = 5,0x 10-4 mbarSilanization t = 10h, Annealing t = 20h

Beijing, SRF2007

Thermal Diffusion: SamplesThermal Diffusion: SamplesVV33SiSi VV33Si at LNLSi at LNL--

NbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

V3Si 5N: 850°C, 1,0x10-3 mbar, 10h+20h

V3Si (Tc = 15,4 K)

V (Tc = 5,0 K)

Beijing, SRF2007

VV33SiSi VV33Si at LNLSi at LNL--

Thermal Diffusion: SamplesThermal Diffusion: SamplesNbNb33SnSn

Liquid Sndiffusion

Double Magnetron

MechanicalPlating

VV33SiSi

Thermal diffusion

ThermalDiffusion

+Plasma

Post Magnetron

Beijing, SRF2007

2) Multilayer:

Double Magnetron: Tc = 17.9 K, ΔTc = 0.02 K

Post Magnetron: the first Nb3Sn 6 GHz cavity has been measured

1) Sn diffusion:

Tc = 16,8 K, ΔTc = 0,16 K,

Nb3Sn 6 GHz cavities has been produced

1) Plasma Silanization:

Tc = 15.7 K, ΔTc = 0.2 K

2) V3Si 6 GHz cavity obtained: Work in progress

NbNb33SnSn

VV33SiSi

SummarySummary

Good News Allen: 6 GHz CavitiesGood News Allen: 6 GHz Cavities

Beijing, SRF2007

6 GHz Cavities6 GHz Cavities

Beijing, SRF2007

• 80 cavities are under fabrication using Scrap Nb

• Flanges are seamless: no brazing, no EB welding

• It is possible to perform more than one RF test a day

The EndNO SAMPLE IS COMPARABLE TO A CAVITY!